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## Come Rain or Shine

Skip to 0 minutes and 7 secondsSo we're launching a weather balloon here, which has got an instrument package tied on to the bottom there in the little white box, which has got sensors for measuring the temperature, and humidity and the pressure. And that's going to measure those variables every few seconds as the balloon rises up to a height of something like 10 or 15 kilometres in the air. And so we get a measure of the temperature and the humidity profile for the whole of the atmosphere rather than just at the surface. It's very useful for working out the temperature of the whole atmosphere, not just what's going on right near a surface.

Skip to 0 minutes and 44 secondsThe balloon that we've just launched is measuring the temperature, and humidity and the pressure as it rises up through the atmosphere. And then it's transmitting those readings back down to our ground station here at the University of Reading atmospheric observatory. And the numbers that you see appearing on the screen, which are changing about once every second, are the readings coming down from the radio sond to our ground station. And they're telling us the position of the balloon relative to where it was launched from. How high the balloon is. So on the graph here, we can see the red curve is showing us the temperature. And where it's been constant here is when the instrument was sitting on the ground.

Skip to 1 minute and 21 secondsAnd as it's decreasing here, that's the balloon rising up through the atmosphere. The blue line is the humidity. So again, you see that as the balloon was on the ground, the humidity wasn't changed very much. But as the balloon started to rise through the atmosphere, the humidity's been increasing. And then the green curve is the pressure that the balloon is measuring. And that's obviously decreasing as the balloon rises because pressure always decreases with height.

# Balloon launch

Watch Pete launch a weather balloon and explain how the radiosonde it carries can be used to measure the temperature, humidity and pressure profile of the whole atmosphere.